docs: def from_config(cls, config, name, section_key="scoring_contexts"):
          """
          Expects:
  
              scoring_contexts:
                  enwiki:
                      scorer_models:
                          damaging: enwiki_damaging_2014
                          good-faith: enwiki_good-faith_2014
                      extractor: enwiki
                  ptwiki:
                      scorer_models:
                          damaging: ptwiki_damaging_2014
                          good-faith: ptwiki_good-faith_2014
                      extractor: ptwiki
  
              extractors:
                  enwiki_api: ...
                  ptwiki_api: ...
  
              scorer_models:
                  enwiki_damaging_2014: ...
                  enwiki_good-faith_2014: ...
          """
          logger.info("Loading {0} '{1}' from config.".format(cls.__name__, name))
          section = config[section_key][name]
  
          model_map = {}
          for model_name, key in section['scorer_models'].items():
              scorer_model = Model.from_config(config, key)
              model_map[model_name] = scorer_model
  
          extractor = Extractor.from_config(config, section['extractor'])
  
          return cls(name, model_map=model_map, extractor=extractor)